Facsimile recording papers



Patented May 31, 1949 FACSIMILE RECORDING PAPERS Frank G. Calkin, Glen Rock, N. 1., assignor to Finch Telecommunications, Inc., Passaic, N. J a corporation of Delaware No Drawing. Application January 9, 1947, Serial No. 721,163

1 Claim.

My present invention relates to facsimile recording paper and more particularly to a dry recording blank which utilizes an electrically discolorable coating and a conductive paper.

Various materials have been used to coat or impregnate a conductive paper so that the surface of the paper will be discolored by the passage of an electric current therethrough.

Primarily, it is an object of my invention to utilize a lead formats in the normal coating composition, since this, from my experiments, produces a clear recording and a much better record with many attending advantages hereinafter described.

The foregoing and many other objects of my invention will become apparent in the following description:

In the formation of my dry blank for facsimile recording, I utilize first a paper which has been impregnated with an electrically conducted material, such as carbon in one of its many forms. Thus, for instance, a paper filled with about 40% graphite furnishes an appropriate conductive base. On this base, I apply a coating according to either of the following formulas:

Lead Formate 1.875 1. 875 Titanium Dioxide. 5.0 5.0 Zinc Dust 0.31 0.31 Nitrocellulose Lacqu 3. 6 Polyvinyl Acetate Solution 10 Thinner (such as Ethyl Acetate) l3. 20

2 obtained in the case of coatings which utilize nitrocellulose as a binder.

The desirable action of lead formate results principally from the fact that it decomposes at a relatively low temperature to produce metallic lead, plus probably some lead oxide. The reaction is as follows:

2Pb(HCO2)2 Pb+PbO+3COz+H2+HCHO While I have here described my invention in connection with the utilization of lead formate as the acting ingredient in the coating, I have also discovered that formates of copper, nickel, cadmium, and bismuth react in substantially the same manner as the lead formate.

In the foregoing I have described my invention solely in connection with a specific preferred embodiment thereof. Since many varations and modifications of my invention should now be obvious to those skilled in the art, I prefer to be bound not by the specific disclosure herein contained, but only by the appended claim.

I claim:

A dry conductive facsimile recording paper and an electrically discolorable coating therefor consisting essentially, in parts by relative weight, of lead formate 1.875, titanium dioxide 5.0, zinc dust 0.31. polyvinyl acetate solution 10 and ethyl acetate 20.

FRANK G. CALKIN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 6,420 Morse May 1, 1849 1,880,449 Hickman et a1 Oct. 4, 1932 1,939,232 Sheppard et al Dec. 12, 1933 2,229,091 Kline Jan. 21, 1941 2,287,348 Hayden June 23, 1942 2,294,150 Kline Aug. 25, 1942 2,310,946 Finch Feb. 16, 1943 2,425,742 Kline Aug. 19, 1947 

